Britain’s National Air Traffic Control Service (NATS) reported a record number of flights last week and issued a warning that the country is running out of airspace.

Air traffic controllers reported a record-breaking 8,800 flights in a single day. They’re warning that, if numbers continue to rise, flights to and from the U.K. could be impacted by significant delays unless the government responds with “drastic modernisation.”

“In the last few weeks we have already safely managed record-breaking daily traffic levels, but the ageing design of U.K. airspace means we will soon reach the limits of what can be managed without delays rising significantly,” Jamie Hutchinson, a director for the NATS, said in a statement.

This summer, the NATS expects to operate 770,000 flights above Britain — 40,000 more than there were last year.

If left unmanaged, the increased traffic could cause 50 times more delays in 2030 than there were in 2015 and 8,000 flight cancellations per year, the NATS said.

“Traffic growth is good news for the economy and means more choice for passengers, but it also puts pressure on the capacity of our airspace infrastructure,” Hutchinson also said. “The U.K.’s airspace was designed decades ago and doesn’t allow us to take advantage of the technology on board modern aircraft that would raise capacity, and also reduce emissions and noise for communities on the ground.”

The U.K. government is working with the NATS to update airspace change policy. They are also asking citizens to submit their ideas on how to improve transportation across the country, including customer service, safety and growth management.